Liquid fuel injection pumps for internal combustion engines



Dec. 29, 1959 w. E. w. NICOLLS 2,913,372

LIQUID FUEL INJECTION PUMPS R INTERNAL COMBUSTION ENGIN Filed March United States Patent LIQUID FUEL INJECTION PUMPS FOR INTERNAL COMBUSTION ENGINES Wilfrid Edward Walter Nicolls, Pinner, England, assignor to CA. Limited, London, England Application March 18, 1957, Serial No. 646,700 1 Claim. (Cl. 103-38) The object of the present invention is to provide in a simple form a liquid fuel injection pump of the reciprocatory type for internal combustion engines.

A pump in accordance with the invention comprises a rotary and reciprocatory cylinder, an axially stationary piston occupying one end of the cylinder, a reciprocatory piston occupying the other end of the cylinder, and means for regulating the stroke of the second piston.

The accompanying drawing illustrates diagrammatically a pump embodying the invention.

In the example illustrated by the drawing there is provided a housing a having at one end a fuel inlet chamber b to which the fuel can be supplied through a pipe 0. Within a bore in the housing is contained a rotary and reciprocatory hollow cylinder at in which are provided a plurality of co-planar inlet ports e which (by rotation of the cylinder) move into and out of coincidence with associated inlet ports f in the housing, these latter ports being open to the inlet chamber b. Also in the cylinder is formed a single discharge port g which (by rotation of the cylinder) can be moved into coincidence with each in turn of a plurality of discharge ports h in the housing, the latter ports being connectible by pipes i to the engine cylinders.

In the end of the cylinder adjacent to the inlet chamber is contained an axially stationary piston which at one end abuts against the end wall of the chamber under the action of a spring k contained in the cylinder. The other end of the cylinder extends beyond the housing, and has secured to it a coaxial toothed wheel m which is driven by motion derived from a gear wheel n in the engine. Or, one face of the wheel m is formed a multilobed cam 0 which by co-operating with an abutment roller p on an extension q of the housing, serves to impart inward axial movement to the cylinder, the reverse movement being effected by a spring r contained in the part q.

In the end of the cylinder adjacent to the wheel m is contained an axially movable piston s which is movable by contact of its outer end with the part of the wheel m around a central hole m therein of smaller diameter than the interior of the cylinder, the inner end of this piston being in contact with the spring k above mentioned.

For regulating vided an axially adjustable stop the stroke of the piston s there is propin t which is carried Patented Dec. 29, 1959 ice by the part q and extends through the central hole m in the wheel m and which abuts against the movable piston. For adjusting the position of the stop pin there is pivoted on the part q a manually or otherwise operable cam u.

The arrangement isrsuch that the maximum stroke of the piston s is obtained when the stop pin t is moved outwards to its fullest extent, the outer end of the piston being then in contact with the wheel m. The minimum stroke results when the pin is moved inwardly to its fullest extent so that the piston then receives no axial movement from the wheel.

By this invention a variable output pump of the reciprocatory type is provided in a simple and convenient form.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

A liquid fuel injection pump of the type specified for an internal combustion engine, comprising in combination a housing having a fuel inlet chamber at one end thereof, and having an axial bore, a hollow cylinder mounted in said bore and capable of rotary and reciprocatory motion relative to said housing, a gear wheel secured in co-axial relationship to the end of said cylinder remote from said fuel inlet chamber for enabling rotary motion to be imparted to said cylinder, and provided with a central hole of smaller diameter than the interior of said cylinder, cam means having interacting parts on said gear wheel and housing for imparting axial movements in one direction to said cylinder during rotary motion of the latter, a spring acting on said cylinder for imparting axial movements thereto in the opposite direction under the control of said cam means during rotary motion of said cylinder, fuel inlet and discharge ports provided in said housing and cylinder for enabling liquid fuel to be admitted to and discharged from said cylinder when the latter occupies appropriate positions, an axially stationary piston occupying the end of said cylinder nearest said fuel inlet chamber, a reciprocatory piston slidably supported within the end of said cylinder remote from said fuel inlet chamber, and movable by contact with the portion of said gear wheel around the central hole therein when said cylinder is moved in the appropriate direction, an axially adjustable member situated at the last mentioned end of said cylinder and arranged to extend through the central hole in said gear wheel into contact with the outer end of said reciprocatory piston, and adjusting means arranged to co-operate with said axially adjustable member for causing the latter to vary the axial position of said reciprocatory piston within said cylinder, and thereby determine the distance through which said reciprocatory piston is movable by and in the same direction as said cylinder.

References Cited in the file of this patent UNITED STATES PATENTS 1,568,170 Le Bret Jan. 5, 1926 2,417,915 Dreisen Mar. 25, 1947 2,667,840 High Feb. 2, 1954 2,827,852 Links Mar. 25, 1958 

